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2 Sheets-Sheet 1.

Patented Nov. 1'7, 1891 I 71/001725?" 721. 63%; g 25 M 2 Sheets-Sheet 2.

E. BERLINE'R. COMBINED TELEGRAPH AND TELEPHONE.

No. 463,569. Patented Nov. 17, 1891.

Wl/ fze/ssas ERS cm, FNOT To all whom it may concern.-

UNITED STATES PATENT OFFICE.

EMILE BERLINER, OF \VASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO THE AMERICAN BELL TELEPHONE COMPANY, OF BOSTON, MASSA- cHUsnTTs.

COMBINED TELEGRAPH AND TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 463,569, dated November 17, 1891.

Application filed June 4, 1877.

Be it known that I, EMILE BERLINER, of \Vashington, in the District of Columbia, have invented a new and useful Improvement in Combined Telegraph and Telephone, of which the following is a specification.

My invention consists in a new and useful improvement in transmitters for electrically transmitting sound of any kind, of which the following is a specification.

It is a fact that if at a point of contact between two conductors forming part of an electric circuit and carrying an electric current the pressure between both sides of the contact becomes weakened the current passing becomes less intenseas, for instance, if an operator on a Morse instrument does not press down the key with a certain firmness the sounder at the receiving-instrument works much weaker than if the full pressure of the hand had been used. Based on this fact I have constructed a simple apparatus fortransmitting sound along a line of an electric current in the following manner.

In Figures 1 and 2 of the drawings,A is a metal plate well fastened to the wooden box or frame, but able to vibrate it sound is uttered against it or in the neighborhood of said plate. Against the plate and touching it is the metal ball C, terminating the screwthreaded rod B, which is supported by the bar or stand (1. The pressure of the ball C against the plate A can be regulated by turning the rod B. included in circuit with an electric battery,

so that they form electrodes, the current passing from one of them to the other. By making the plate vibrate the pressure at the point of contact a becomes weaker or stronger as often as vibrations occur, and the strength of the current is thereby varied accordingly, as already described. By placing now, as is shown in the drawings, one such instrument The saidball and plate are of the instrument Fig. 1 will be reproduced 5o by the plate of the instrument Fig. 2, for as the vibrations of the transmitter Fig. 1 caused by the sound will alternately weaken and strengthen the current as many times as vibrations occur, the diaphragm of the receiver will be caused by these electrical variations to vibrate at the same rate and measure. The latter vibrations being communicated to the surrounding air, the same kind of sound as uttered against the transmitter Fig. 1 will be reproduced at the receiver Fig. 2, or in as many other receiving-instruments as are situated Within the same electric circuit.

It is not essential that the plate should be of metal. It can be of any material able to vibrate, if only at the point of contact s itable arrangement is made so that the current passes through that point. The plate maybe of any shape or size, or other suitable vibratory media may be useda wire, for example. Any other metallic point, surface, wire, 820., may be substituted for the ball. There may be more than one point of contact to be affected by the same vibrations. Both of the electrodes may vibrate, althoughit is preferable thatonly one should. It the uttered sound is so strong that its vibrations will cause a breaking of the current at the point of contact in the transmitter, then the resultat the receiving-instrument will be a tone much louder, but not as distinct in regard to articulation.

I have also embodied my invention in and used it in connection with some other forms of apparatus.

In the drawings, Fig. 4 represents a detached view of the vibratory diaphragm, showing its relative situation to the poles of the galvanic current. Fig. 3 represents a view of a complete apparatus; Fig. 5, a view of the diaphragms arranged to receive and transmit the sound waves; and Figs. 6, 7, and 8 modifications of the vibratory diaphragm.

In the drawings, the letter A represents a diaphragm or plate of thin metal, of limited conductive capacity, such as iron, steel, German silver, platinum, secured in the frame m m in the box F in any convenient manner.

The letter y represents a ring resting against one side of said diaphragm and capable of being made to bear upon the same with more or less force by means of set-screws n, in order that the tension of the diaphragm may be regulated.

The letter B represen s a screw or pin of metal, pointed at one end and mounted in a cross-piece d in such position that the point will be in contact with the diaphragm A. The diaphragm A is connected with one pole of a battery by means of a wire a, and the pin or screw B with the other pole by means of a wire I).

The box F of Fig. 3 is provided with a tube K, to which the ear of the operator may be applied, in order to hear the sounds produced by the vibratory diaphragm when the instrument is employed as a receiver, and a tube 0, through which he can speak when employing the instrument as a transmitter, so that the operator is not in need of moving the instrument or moving his head while carrying on a conversation.

Instead of employing a single vibratory plate, as shown in Figs.1,2, 3, 4, and 5, in each instrument, two such plat-es may be employed,

as illustrated in Fig. 8, said diaphragms being connected to the respective poles and in contact with each other at their edges, as shown in Fig. i

The diaphragm of myimproved receiver or the diaphragm of any magneto-receiver (such as those described by Alexander Graham Bell in hisPatent No.174,465 of March 7,1876, and

in his Patent No.186,787 of January 30, 1877) will receive a particularly strong shock at the setting in and sudden cessation of the current when a ticking sound will be heard from the plate; but aweakening of the current alone can also be observed most distinctly and accurate- 13; by making, for example, a connection within the same circuit by a wire and the blade of a knife k, Fig. 4. W hen scraping the wire end over the blade of the knife, this scraping is distinctly audible on the plate. Here the current is never entirely interrupted, yet the minute elevations and cavities on the blade, caused by the structure of the steel and which again cause minute alterations in the in tensity of the current, are suificient to shake or vibrate the platewith varying intensity, thus rendering again the same peculiar scraping noise. it, now, the plate of one instrument, as in Figs. -1 or 5, is vibrated by sound-waves (which happens whenever any kind of sound is uttered or is produced bytmusical instruments in its neighborhood) every wave or vibration that strikes the plate produces be tween the two sides of the contact a variation of pressure, which causes a variation of resistance at that point, and therefore a variationin the strength of the passing current, audit the sound is sufiiciently strong it will break the circuit at said point of contact, the variations in the current thus produced causing similar vibrations in the plate of the receiving-instrument. The essential part of the apparatus is the point of contact, which must otter a resistance to the current.

' 'It is not necessary in the transmitting apparatus that the plate should be of conducting material, for any substance capable of vibration will answer, if only at the point of contact provision is made for the current to pass. It is sometimes convenient to use a vibrating plate in the form of a reflector, as shown in Fig. 6, for concentrating the sound, or the diaphragm may be provided with a number of apertures to disperse the sound, as shown in Fig. 7. These apertures prove advantageous with strong sounds, particularly the hissing sounds, as while the soundwaves are rushing toward the diaphragm, those touching the plate are repelled and par tially destroy the following waves, just as sea-waves when forced against a cliit will be thrown back destroying those directly behi nd. The holes permit most'of the waves to pass to the other side of the plate, making the vibration of the plate more perfect and'even.

I will here describe a recording apparatus, which, however, I do not claim.

In Fig. 3, G is a galvanometer, which is located in circuit with the contact-pieces or electrodes A B, and which serves as a convenient means for ascertaining the adjustment of the contact-pieces of the transmitter, so that acurrent shall pass. i p i isaRuhmkorfit coil orv induction apparatus. \Vhen a current passes through the primary coil 1) and suddenly is broken, a spark will rush over between the ends of the secondary coil it at q. This spark is accompanied by a, peeculiar sound dueto the electric discharge, and if we bring between the ends of the secondary the connecting-points r r 9' r a spark will occur between each of them, provided they are near enough to each other, and the peculiar sound will be heard bet-ween each of them. I now arrange a strip of chemicallyprepared paper or other substance 11. to be drawn by clock-work T between the ends of this secondary wire at q. Said strip can be prepared in such a way that each. spark will produce a mark upon it. If, therefore, the plate A vibrates by sound, each, "ibration causing a break of contact will produce a spark at q, and the stripbeing drawn through, a'sucoession of marks will be produced upon the strip according to the number of vibrations caused by the sound; but at the same time the sound which was uttered at theplate A will be heard from the sparks rushing over the points r, r, r, r, and q,because every spark produces one wavein the atmosphere in which it occurs, and a certain number of waves will therefore produce certain tones. Therefore the same sound which is uttered against the. plate A will be heard from the sparks.

The

scraping of the wire end on the kniferblade k, as in Fig. 4, in the primary current will also be heard between the wire ends of the secondary current at r, r, r, 'r, and g. This per mits a number. of designs for a receiving apparatus within the secondary current. For instance, initials, ornaments, &c.,.consisting of a number of metal pins can be constructed in such'a way that whenever a tone is pro-.

duced against the plate A a spark will rush over said metal pins, and at the same time their sound is produced will render the design visible in illuminated characters.

By making the person of the operator a part of the secondary circuit and discharging the sparks in the body in the neighborhood of the ear the sound will be more particularly apparent.

It will be observed that in Figs. 1 and 2 one of the electrodes presents aconvex curvilinear surface like a rounded knob. This possesses some advantages, among which are ease of construction and durability, because it does not wear away the opposing electrode as much as a sharp one would, and when the contact with the vibrating body is made of such a form the freedom of the vibration is less interfered with. V

I do not claim that I am the first inventor of the art of transmitting vocal and other sounds telegraphically by causing electrical undulations similar in form to the soundwaves accompanying said sounds. Neither do I claim that I am the first who caused such electrical undulations by varying the resistance of an electric circuit in which a current was passing.

I do not herein claim the novel form of vibratory-plate receiver which I have described, because that is a subject of claim in another application.

I claimv 1. The method of producingin a circuit electrical undulations similar in form to soundwaves by causing the sound-waves to vary and forming 'part of a circuit which includes a battery or other source of electric energy and adapted to increase and decrease the resistance of the electric circuit by the variation intpressure between them caused by the vibrational movement of said sensitive plate.

The combination, with the diaphragm and vibratory electrode, of a rigidly-heldopposing electrode in constant contact with the vibratory electrode, substantially as described.

4. In a telephonic transmitter, a vibrational plate made concave for condensing the sound, substantially as set forth.

5. In a telephonic transmitter, a vibrational plate provided with one or more apertures, as and for the purposes set forth.

6. A speaking-telephone transmitter comprising a diaphragm or disk sensitive to soundwaves, combined with a rigidly-held but adjustable electrode in contact with the same, whereby the electric current is transformed into a series of undulations corresponding with the vibrations of said diaphragm.

In testimony that I claim the foregoing I have hereunto set my hand in the presence of the subscribing witnesses.

EMILE BERLINER.

lVitnesses:

J. A. RUTHERFORD, JAMES L. NoRRIs. 

